Vacuum-producing apparatus



.uhdnzuaiou Aug. 29, 1939.

`vAcuuu-Pxzonuczmci APPARATUS ATTORNEY m N ||I d' l' IH l fr' A 1 Il :I1 t:

WITNESSES l Aug. 29, 1939. R.' AfBowMAN vAcuunu-PRonucmcf APPARATUS Filed .myV 23, 1936 sheets-'smi z mvENToR RA .BowM/ANk n BY V5 M ATTORNEY A Nmzmazou d Patented Aug. 29,' 1939 n STATES 2,170,802` y VACUUM-PRODUCING APPARATUS Pennsylvania Application July 23, 1936, Serial No. 92,089

7 Claims.

My invention relates to vacuum producing apparatus, more particularly to such apparatus hav!-` ing evaporative condenser apparatus, and it hasl circulating fans, or other means, are provided so` that the circulation of air over each condenser element may be initiated and terminated simultaneously with initiation and 'termination of au operation of the associated ejector. l

These and other objects are effected by my in- I vention as will be apparent from the following description and claims taken in connection with the accompanying drawings, dagrammatically illustrating the invention and forming a part of this application, in which:

Fig. l is a side elevation, partly in section, of apparatus inaccordance with my invention; and,

Par

seen from the right of Fig. l.

In the form shown on th'e drawings, I have illustrated my invention as embodied in steam jet refrigerating apparatus. The latter includes an evaporator lilin which cooling of water is efiected by partial evaporation thereof under reduced pressure. The water to be cooled is conveyed to the evaporator Iii through a conduit l I and sprayed thereinby any suitable means, such as by slotted conduits i2. A valve I3 in Vthe conduit il, actuated byv a float i4 in response to the level of water in the evaporator ID, controls the admission of water to be cooled. 'I he cooled water is conveyed to the point of use through a conduit l5 connected to the bottom of the evaporator il), a suitable pump `(not shown) being provided. In the present embodiment, the evaporator Ml is preferably supported at a somewhat elevated position, as by means of columns or posts it.

A' plurality of ejectors, such asthe ejectors `il and i8, are provided for removing the vapor from the evaporator lll. Each ejector has its suction inlet I9 connected to a vapor outlet 2| at the top of the evaporator. Each ejectorcomprises nozzles 22 supplied with motive steam from a condit , the exterior thereof.

Fig. 2 is an end elevation, partly in section,as

duit 23. It may also have a starting nozzle 2t Asupplied Witlifsteam from the conduit 23 through a branch conduit 25 and a valve 26. A valve 2l, provided in the conduit 23, is adapted to control. the ow of steam to both sets of nozzles of the ejector I'Land a similar valve 2l is provided for the ejector it. When the starting nozzle 2d is employed, automatic control mechanismfor operating the valve 2t 'in starting operation of the ejector, as described and claimed in Patent 2,033,844 of D. W. R. Morgan and J. W. McNulty is preferably provided. Inasmuch as such starting nozzle and the control therefor are not an essential part of the present invention, the control therefor is not described herein.A

According to the present invention, each ejector is provided with a separate condenser or condenser element for condensing the exhaust fluid therefrom, the condensers for the ejectors l 'i and it being indicated at 2B and 29, respectively. Each condenser comprises heads 3l andu 32 and a bank of tubes 33 connected thereto and extending therebetween. The tubes are preferably provided with fins or extended heat transfer surfaces on 'Ihe tube bank preferably comprises a plurality of superimposed horizontal rows of tubes, and the tubes of adjacent rows may be arranged in onset or staggered relation as shown in Fig. 2. Thehead 3l is provided with a horizontal partiticnd, disposed just below the uppermost row of tubes and dividing the head 3l into an inlet chamber 35 and an outlet chamber 3d, the inlet chamber :i5 being connected to the outlet of the ejector through a suitable conduit 3l. The tubes connected to the outlet chamber 36 yconstitute air cooler tubes serving to cool or de-vap'oriZe the air and non-condensable gases discharged from the lower tubes into the head 32,

While the tubes connected to the inlet chamber 35 serve primarily to condense steam. It will be apparent that the partition 3d may be formed or disposed so as to connect any desired number of air cooling tubes to the outlet chamber 36. Suitable air removal apparatus described below is connected to each outlet chamber 36. Vertical side Walls 3B are preferably provided on each side of*`` the tube bank between the heads 3i and 32 to form a casing or passage for vertical flow of air therethrough over the Vcondenser tubes.

In accordance with thepresent invention, the condensers are cooled by evaporative cooling; that is, water is sprayed onto the outer surfaces of the tubes and a stream of air passed over the wetted surfaces to effect cooling by evaporation of water` in the air stream. Each condenser is provided with suitable air translating apparatus, for example, a propeller fan 39 driven by an electric motor 4I. The fan is disposed above the tube bank and effects a downward ow of air over the condenser tubes. A fan housing 42 encompasses the propeller fan 39, and a diverging duct member or fitting 43 serves to convey and distribute the air from the fan to the tube bank.

A series of spray nozzles 44'is disposedlalong each side of the tube bank at the top thereof, and arranged to distribute a spray of water over the top of the tube bank. While the water spraysare directed more or less transversely of the downward stream of air, in order to distribute the spray over the top of the tube bank, the general direction of flow of the spray water over the surfaces of the tubes is downwardly, in the same direction as the flow of air. I find that such an arrangement is highly advantageous in reducing resistance to ilow of air, particularly as compared with an arrangement in which the water sprays are directed in a direction opposite to the flow of air.

position by means of columns 46. The drip pan. 45 is formed with openings through which thev columns extend, and the edges of the openings are welded to the columns to prevent leakage of water and to support the drip pan on the columns. The

space between the bottom of the condensers and the drip pan is enclosed by a louveredA structure 41, also common to the 'two condensers. The structure comprises horizontally-extending louvers each having an outwardly inclined portion 48 and a'horizontal portion 49, and arranged to form four vertical louvered walls providing a rectangular enclosure about said space.

The condenser'tubes 33 are preferably inclined l to the right,l as seen in Fig. 1, causing the condensate to ldrain by gravity into the. head 32. From the latter, the condensate from each condenser is drained \by gravity first through a branch conduit 5I and then through a common conduit 52 to a pump 53. From the latter, the water is vconveyed from a conduit 54 into the drip pan 45. The branch conduits 5| extend downwardly a sufcient distance before they are joined to provide a loop or hydrostatic seal therebetween wher; one condenser is in operation and the other 1s no The outlet chambers 36 of the condensers 28 and 29 are connected to suitable air removal apparatus through branch conduits 62 and 63 and a common conduit 64. Valves 61 and 68 are connected in the branch conduits 62 and 63 and are actuated by solenoids 69 and 1I, respectively.

The air removal apparatus preferably comprises a rst stage air ejector 55 and a second stage air ejector 56. An intermediate condenser 51 is connected to the outlet of the ejector 55,*the condensate from said condenser being drained into the head 32of one of the condensers by means of a conduit 59 arranged in the form of a seal, while the uncondensed fluid is withdrawn by the second stage ejector 56. An after condenser 58 is connected to the outlet of the latter, the condensate a conduit 6I to the drip pan 45, while the uncondensed uid is vented to the atmosphere through a vent 60.

The ejectors 55 and 56 are supplied with steam from the conduit 23, valves 65 and 66 being provided for the respective ejectors. These valves may well be manually controlled, since it is desirable to maintain the .air removal apparatus in continuous operation, even thouglf operation of the main ejectors may be intermittent. However, it will be apparent that the valves may be automatically controlled so as to be in operation only at such time as at least one condenser is in operation.

The drip pan 45 is provided with a sump tank 12, to which a conduit 13 is connected for removing the unevaporated spray water, together with the condensate collected therein, to be re-delivered to the sprays 44. The conduit 13 is connected to the inlet of pump 14, which discharges the same into a conduit 15. One feature of the present invention resides in the use of the unevaporated spray water, which has been cooled substantially to the wet bulb temperature of air circulated over the condensers,l as circulating water in the intermediate and after condensers. Accordingly, the conduit 15 is connected to the intermediate condenser 51, and the unevaporated spray water is circulated first through the intermediate condenser 51 and then through the after condenser 58. From vthe latter, it is conveyed through a conduit 16 and branch conduits 11 and 'I8 connected to the spray nozzles 44 of the condensers 28 and 29, respectively. The branch conduits 11 and 18 are provided with valves 19 and 8 I, provided with solenoids 82 and 83, respectively.

A control system for automatic operation of the above described apparatus is preferably provided. I preferably design the control system so as to eisect admission of steam to the ejector, operation of the air fan, delivery of water to the spray nozzles, and communication with the air removal apparatus simultaneously with the operation of each ejector. In the drawings, I show a preferred form of electrical control supplied with current 'from line conductors L-I and L--2. The control includes a thermostat 84 responsive to the temperature of the cooled or chilled water discharged from the apparatus through the conduit I5 and connected to the movable arm 85 of a switch mechanism 66. 'I'he latter includes acontact 81 connected to a conductor88 for l controlling the ejector I1 and its auxiliaries, and

a contact 89 connected to a conductor 9I for controlling the ejector I 8 and its auxiliaries. v The arm 85, which is connected tothe line conductor L-I is arranged to engage the 'contacts 81 and 89 successively upon successive predetermined increases in the temperature of the chilled Water. The solenoids 20, 69, and 82 and the f an motor 4I associated with the ejector I8 are controlled by the conductor 88, preferably having one terminal connected to the conductor 88 and the other terminal connected to the line conductor L-2.. Similarly, the solenoids and the fan motor associated with the ejector I8 are preferably connected in parallel between the conductor 9| and the line conductor L-2 so as to be simultaneously energized upon energization of the conductor 9|.

Operation The operation of the above-described apparatus is as follows: To initiate operation of the refrigerating apparatus, operation of the condensate pump 53, the circulating water pump 14, the air ejectors 55 and 56, land circulation of the chilled water are first initiated. Assuming a maximum refrigerating demand, this is represented by a suiliciently high temperature of the chilled water to cause the switch arm 85 to be moved by the thermostat 8l to engage both contacts 81 and 89, thereby energizing circuits 88 and 9| to effect operation of both ejectors.

Both valves 21-21' (and the valves 26) are opened to supply steam for operation of the ejectors I1 and I8. 'I'he electors I1 and I8 withdraw vapor from the evaporator I and discharge the same, together with the motivating steam, into the condensers 28 and 29, respectively. The removal of vapor from the evaporator I0 effects a reduction in pressure therein, whereupon a portion of the water circulated therethrough vaporizes and is cooled. The steam discharged from each ejector passes through the inlet chamber iid of the associated condenser into the condensing tubes connected to said inlet chamber, in which tubes the major 4 portion of the steam is condensed. The air and non-condensable vapors then flow, from the head 32, through the tubes in the uppermost row, in which they are cooledv and partly devaporized, to the outlet chamber it, from which they are `conveyed through the connecting conduits to the air removal apparatus. The condensate from the condensers is drained from the heads 32 through the conduits i and 52 to the condensate pump 53, from which` it is discharged through the conduit 54 into the drip pan i5.

The fan 39 of each condenser eiects downward flow o f air through the vertical passagethe latent heat abstracted from the steam within the tubes is largely used as latent heat to vaporize water on the exterior surfaces of the tubes, the water vapor being carried away with the air stream. The air then iiows downwardly from the tube bank into the space enclosed by the louvered structure 41, and then passes horizontally outwardly between the louvers. The unevaporated particles of water that are carried downwardly b y the air stream are collected in the drip pan 45, and the louvers assist in separating the smaller, particles which would otherwise be carried away by the air stream.

The unevaporated spray water collected by the drip pan I5 is removed from the sump 12 thereof and conveyed through the conduit 13 to the pump 14,from. which it is discharged vinto the conduit 15. The latter conveys thewater to the intermediate condenser 51, through which it flows and effects condensation ofthe steam and vapor distial evaporation of the water in the air stream, the temperature of, the water being rapidly reduced to that of the wet bulb temperature ofthe air. The water then again serves to provide evaporative cooling as above described.

When the cooling load drops to a point such that the operation of one ejector is suiiicient to `provide Kthe desired temperature, the temperaand the operation of its auxiliaries are continued so that the ejector I1 and the condenser, continue to operate in the same manner as before. In this case, the air leaving the condenser 28 may move' outwardly through the entire louvered structure 41 so that the velocity thereof may be somewhat reduced. Inasmuch as the ejectors are provided with separate condensers, the shutting down of the ejector I8 will not result in back flow of vapor from the condenser into the evaporator I0, except a momentary flow incidental to equalization of pressure between the evaporator I0 and the condenser 29. This arrangemeht eliminates the necessity of a valve between the evaporator and the suction inlet of each ejector.

Upon' further decrease in cooling load and drop in the temperature of thechilled water in the conduit I5, the switch arm 85 disengages the contacts 81, thereby deenergizing th'e conductor 88. The flow of steam tothe ejector I1 and the operation of its auxiliaries is then shut down, thereby terminating removal of the vapor from the evaporator I0. In the illustrated embodiment, the air removal apparatus continues to operate during intermittent operation of the ejectors, in order that vacuum for air removal may be maintained. It is to be understood, however, that any suitable control for the air removal means, known in the art, may be. provided.

Upon increase in chilled water temperature, the arm 85 is moved upwardly by the thermostat 8d first into engagement with the contact 81, thereby again initiating operation of the ejector I1 and its auxiliaries in the manner above described.

Upon further increase in temperature of the that I have provided a novel arrangement of evaporative condenser for steam jet refrigerating apparatus. A desirable feature is the provision of separate condensers. together with separate air circulating fans, whereby circulation of air may be terminated upon shutting down of the associated ejector.

Reference is made to my copending application, Serial No. 186,929, filed January 26, 1938, which describes and claims subject-matter divided from this application.

While I have shown my invention in but one form, it will be obvious to those skilled inthe art that it is not so limited, but isY susceptible of vari- 4ous changes and modiiications, without departing from the spirit thereof, and I desire, therefore, that only such limitations are placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is: 1. In a vacuum producing apparatus, the combination of a vacuum chamber, a; plurality of ejectors for withdrawing vapor from said chamber to effect a vacuous condition therein, a separate condenser element connected to each'ejector, sep.

arate air circulating means for each condenser, means for individually rendering said ej ectors operative or inoperative, and means for initiating and terminating operation of the air circulating means of each condenser element simultaneouslyv with initiation and termination of operation of the associated ejector.

2. In refrigerating apparatus, the combination of evaporator means, a plurality of ejectors connected to said evaporator means, a separate condensing element connected to each ejector, means for circulating cooling fluid in heat-exchanging relation with said condensing elements, means for rendering said ejectors individually operative or inoperative, and means for initiating and terminating circulation of cooling fluid in heat exchanging relation with each condenser element simultaneously with initiation and termination, respectively, of operation of the associated ejector.

3. In refrigerating apparatus, the combination of evaporator means, a plurality of ejectors for withdrawing vapor from said evaporator means, a condenser element for each ejector,means for circulating air over each condenser element, means for supplying a film of water to the air cooled surfaces of each'condenser element, means for successively rendering said ejectors operative in response to successive increases in refrigerating load, and means for initiating and terminating circulation of air and water over each condenser element simultaneously with initiation and termination, respectively, of the. associated ejector.

4. In refrigerating apparatus, the combination of an evaporator, a plurality oi' ejectors for removing vapor therefrom, an evaporative condenser for each ejector, means for wetting the surfaces of said condensers, means associated with each condenser for circulating air over the wetted surfaces thereof, and means whereby each ejector and the associated air circulating means may be simultaneously rendered operative or inoperative in response to the temperature of said evaporator.

5. In refrigerating apparatus, the combination of an evaporator, a plurality of ejectors for removing vapor therefrom, an evaporative conf denser for each ejector, means for wetting the vsurfaces of said condensers, means associated with each condenser for circulating air over the wetted surfaces thereof, means for rendering said ejectors `individually operative or inoperative, and means for rendering each air circulating means operative or inoperative simultaneously with its associated ejector.

6. In refrigerating apparatus, the combination of evaporator means; a plurality of ejector-condenser units for effecting pressure reduction in said evaporator means; each ejector-condenser unit comprising an ejector connected to said evaporator means, a separate evaporative condensing element for the ejector, means for circulating air over the surfaces of said condensing element, means for spraying water onto said surfaces, an air outlet for the condensing element, and means for controlling the admission of motive fluid to the ejector; and means for rendering said ejector-condenser units individually operative or inoperative, said last-mentioned means initiating and terminating admission of motive fluid, opening of the air outlet, and operation of the air circulating means and the water spray means of each ejector simultaneously upon initiating and terminating operation, respectively. of the ejector-condenser unit.

'7. In refrigerating apparatus, the combination of an evaporator chamber, a plurality of ejectors having their suction inlets connected to said chamber. means for individually rendering said ejectors operative, condenser elements connected to' the outlets of the respective ejectors, common means for removing air and non-condensable vapor from said condenser elements, and means for initiating and terminating com'- munication between the condenser element of one ejector and said air removal means simultaneously with initiation and termination, respectively, of operation of said one ejector. I

ROBERT A. BOWNAN. 

